The fifth Gordon Research Conference on Extrachromosomal Elements will be held at Colby-Sawyer College, New London, New Hampshire from July 14-18, 1986. This Conference will emphasize recent advances on extrachromosomal elements in prokaryotes, but approximately one-third of the presentations will cover eukaryotic extrachromosomal systems. The titles of the nine sessions which will be held are listed below. I. Replication of Bacterial Plasmids II. Bacterial Plasmid Segregation and the Cell Division Cycle III. Transposable Elements in Prokaryotes and Eukaryotes IV. Plant Extrachromosomal Elements V. Replication and Segregation of Eukaryotic Extrachromosomal Elements VI. Plasmid Transfer and Recombination in Bacteria VII. Mitochondrial DNA VIII. Extrachromosomal Specialized Functions I. IX. Extrachromosomal Specialized Functions II.